Original *kw was lost before back vowels in Latin, as in *sekwondos > secundus ‘following, next’, *kwolō > colō ‘I cultivate’, in the second half of the third century BC (Meiser 1998: 92; Weiss 2020: 165). The spelling with <qu> was maintained (or reintroduced) in some words (e.g. equus ‘horse’, aequus ‘equal’, on the basis of parts of the paradigm where /kw/ occurred before a non-back vowel; quottidiē ‘every day’, which is attested later than cottidiē, Ernout and Meillet 1985: 146), notably in quom for cum ‘when, since’ < *kwom (and by extension, also for cum ‘with’ < *kom).

Mancini (2019) provides a useful summary of the history of the spelling <xs> for <x>. The earliest example in a Latin inscription is exstrad (twice) in the SC de Bacchanalibus (CIL 12.581) of 186 BC, although two instances of faxsit in testimonia of the Laws of the Twelve Tables are argued by Mancini to reflect an edition carried out by Sextus Aelius Paetus, curule aedile in 200 BC, consul 198, and censor in 194. In addition, the Marrucinian ‘Bronze of Rapino’, datable to the second half of the third century BC, has lixs ‘law’ < *lēg-s. In a corpus of inscriptions from this period until 30 BC, Mancini counts 135 occurrences of <xs> beside 1,310 of <x> (<xs> thus making up 9% of the total).

The word populus goes back to *poplos, and the unepenthesised form is still attested in inscriptions from the fifth to the early second century BC; populus is first seen in inscriptions dating from the second half of the second century BC (Sen 2015: 149–51). The word pūblicus ‘public’ and names such as Pūblius ultimately go back to derived forms like *poplikos, *poplii̯os etc. At some point the first vowel became /uː/ and the second *p became /b/. It is commonly supposed that this was due to contamination with pūbēs ‘manpower, adult population’, but a sound change is not ruled out.

Around the middle of the third century BC, the diphthong /εi/ underwent monophthongisation to close mid /eː/; about a century later, this /eː/ was raised further to /iː/, thus falling together with inherited /iː/ (see p. 000). We will see that neither <ei> nor <e> for /iː/ – and for /i/ which results from shortening of /iː/ – are very well attested in the corpora. Nonetheless, even after the first century BC/Augustan period a few plausible examples of each do pop up, in the case of <ei> in one of the Claudius Tiberianus letters, which in general often seem to preserve old-fashioned spelling, and, in the case of <e>, at Vindolanda.

The wax tablets from Herculaneum, presenting a corpus very similar in use and purpose to that of the TPSulp. tablets, contain a very small number of apices, consisting of 16 instances on 14 words across 5 tablets (out of a total of 40 documents, including one copy). For the sake of completeness, I give all examples below this paragraph. 12 examples out of 16 are on long /aː/ and /ɔː/, 1 is on /ɔ/ arising by iambic shortening, 1 is on /ɔ/, 1 is on /ae̯/, and 1 is on /uː/. It is a remarkable coincidence that one of the words is pálós, one of the examples used by Quintilian of where an apex is appropriate. No overarching rationale for the use of apices arises, particularly given the extremely fragmentary material.

In the late third or early second century BC the off-glide of the diphthong /ai/ was lowered to /ae̯/, leading to a change in spelling from <ai> to <ae> (see p. 000). The use of <ai> for <ae> in inscriptions of the first–fourth centuries AD, especially in genitive and dative singulars of the first declension, is actually not particularly difficult to find, even in quite large numbers (although given the thousands of examples of <ae>, the frequency is probably still very low). Some, but not all, of these will be due to Greek influence, misreadings, or mistakes by the stonemason. Use of <ai> seems to have been one of the spellings favoured by Claudius (Biddau 2008: 130–1), but examples can still be found long afterwards.

The use of i-longa is very different from that of apices in the tablets of the Sulpicii and the tablets from Herculaneum. For one thing, i-longas are far more common than apices. In the TPSulp. tablets I count 799 instances of i-longa (compared to 76 apices), which appear in all but 16 of the 127 documents. In the TH tablets they appear in 26 documents out of 40, and I count 243 instances in total. They also differ in the range of phonemes which they represent. Adams (2013: 104–8) discusses the use of <ì> in the tablets of the Sulpicii at some length, although without a rigorous collection of examples. He observes that it is found for long /iː/ (as might be expected on the basis of the grammatical tradition), for short /i/, and for /j/, both word-initially and word-medially between vowels. The large numbers of i-longa in the tablets of the Sulpicii make a full investigation difficult, but 163 cases are used to write a synchronic short vowel (with 19 of these being vowels which were originally long), which equates to 20% of the total.

The writers on language were aware that <c> had previously been used for /g/ (e.g. Terentianus Maurus 210–211, 894–901 = GL 6.331.210–211, .351.894–.352.891). Instances of <c> for <g> are occasionally found in my corpora, but it is hard to take them seriously as examples of old-fashioned spelling. In the curse tablets there are scores, if not hundreds, of instances of <g> in the corpus as a whole, and in most cases the few apparent cases of <c> are probably to be put down to the difficulty of distinguishing <c> from <g>, either in the writing or reading of small letters on a thin piece of soft metal which is generally then subject to folding and unfolding, abrasion, water and other types of damage etc. – cf. Väänänen’s (1966: 53) comment that instances of <c> for <g> at Pompeii are ‘simple writing errors’ (‘simples erreurs d’écriture’). For similar reasons, the few instances of <c> for <g> in the graffiti from the Palatine are not to be taken seriously.

A number of different changes took place to reduce original geminate consonants in Latin. In addition, there was another rule (or rules) which produced geminates out of original single consonants. Since these changes did not take place at the same time, and were not necessarily reflected in spelling at the same rate, I will discuss them here separately.

Adams (1995: 97–8, 2003: 531–2) collected most examples of apices in the Vindolanda tablets in Tab. Vindol. II and III. Including some doubtful cases, he counts 92 instances. We can add a further 7 found in the more recently published tablets, and 6 which he omitted. With the new cases we have a total of 105 instances of apices (Table 35), of which 82 = 78% are on long vowels, and 19 = 18% are on short vowels, with a further 2 = 2% on vowels which were short but used to be long, and 2 = 2% on vowels of uncertain length (Table 36).

In the course of the second century BC, /ɔ/ became /ɛ/ after /w/ and before a coronal, other than a single /r/ (Weiss 2020: 152), for example uoster > uester ‘your’, uoto > ueto ‘I forbid’, aduorsom > aduersum ‘against’. The earliest inscriptional example comes in the Lex repetundarum of 123–122 BC (CIL 12.583), where we find a single example of auersum beside five cases of the spelling <uo>. I have found 6 instances of the <uo> spelling dated to the first century BC, beside 52 examples of <ue>.